1. Field of the Invention
The present invention relates to a data processing apparatus such as an image reading apparatus or a printer.
2. Description of the Related Art
A data processing apparatus used as an image reading apparatus or a printer includes an image reading head for reading data formed on a document or a printing head for printing data onto a printing sheet. The data processing apparatus also includes sheet conveying rollers for conveying a sheet from a hopper to a stacker. For example, one type of image reading apparatus having an auto-document feeder (ADF) is shown in FIG. 50 in the attached drawings. In FIG. 50, the image reading apparatus 190 comprises a hopper 191, an image reading head 192, a stacker 193, and a feeder 194 including sheet conveying rollers. Documents are automatically fed from the hopper 191, through the image reading unit 192, to the stacker 193, by the feeder 194. This type of image reading apparatus 190 can efficiently process data since a plurality of documents can be automatically fed.
Another type of image reading apparatus having a flat bed is shown in FIG. 51 in the attached drawings. The image reading apparatus 200 comprises an image reading window (flat bed) 201 and an image reading unit 202 arranged inside the flat bed 201. In this apparatus, a document is manually set on the flat bed 201 and an image reading operation is carried out sheet by sheet. This type of image reading apparatus is not efficient when a plurality of documents are to be processed because only one document can be set on the flat bed 201. However, this type of image reading apparatus is simple in construction and inexpensive, as compared with the ADF-type image reading apparatus, so that the flat bed-type image reading apparatus is sometimes preferably used, in particular, for personal individual use, when it is not necessary to handle many documents.
These image reading apparatuses suffer from a problem in that the image reading apparatus requires a larger space around it. For example, in the ADF-type image reading apparatus, the stacker 193 projects laterally from the casing of the image reading apparatus and the hopper 191 projects upwardly from the casing of the image reading apparatus. Therefore, a larger area is needed for placement of the image reading apparatus. Also, it is not possible to place any article on the image reading apparatus because of the provision of the upwardly projecting hopper 191 so that the space above the image reading apparatus cannot be utilized.
In the flat bed-type image reading apparatus, there is no stacker or hopper projecting outwardly from the casing of the image reading apparatus, and the image reading apparatus is relatively compact. However, a document must be set on the flat bed 201, and the space above the image reading apparatus cannot be utilized.
In Japanese Patent Application No. 6-509826, the inventor of the present invention has proposed an image reading apparatus by which a space around the image reading apparatus can be effectively used. FIGS. 52 and 53 show this type of image reading apparatus. This image reading apparatus 210 comprises a box-shaped casing having upper and lower cavities, and a drawer 211 arranged in the upper cavity. A hopper 215 and an image reading head 212 are arranged in the drawer 211, and the lower cavity serves as a stacker 214. A U-shaped sheet conveying path 213 is provided to convey documents from the hopper 215 through the image reading head 212 to the stacker 214.
The top wall of the casing of the image reading apparatus is solid and no functional element is arranged in the top wall of the casing. Therefore, it is possible to place an article such as a personal computer on the casing of the image reading apparatus, and the image reading apparatus can be used in a restricted area, so that the space around the image reading apparatus is available for use. The present invention is intended to further improve this type of image reading apparatus.
Recently, there have been increasing demands for an image reading apparatus which can read not only data on the upper surface of the document, i.e., but also data on the lower surface of the document.
In addition, a printer can be formed, using the constructional features of the above described apparatus 210, by positioning a printing head in place of the image reading head 212 in the drawer 211. In this case too, the space utility around the printer is high, and it is further desired that the printer can print data not only on the upper surface of a printing sheet, i.e., but also on the other surface of the printing sheet.
Further, one user may wish to process (read or print) data on both surfaces of a sheet, but another user may wish to process data on only one surface of a sheet. If the data processing apparatus is completely designed in such a manner that it can process data on both surfaces of a sheet, a user who wishes the data processing capability on only one surface of a sheet may think that the data processing apparatus includes an extra function. On the other hand, if the data processing apparatus is designed in such a manner that it can process data on only one surface of a sheet, a user who wishes the data processing capability on both surfaces may think that data processing apparatus is well enough equipped. Therefore, it is desirable that an extra function can be optionally provided to the data processing apparatus.
Also, it is not desirable that the data processing apparatus becomes large in size even if the data processing apparatus can process data on both surfaces of a sheet, so that the space around the apparatus can be used.